Due to different conditions the voltage at the output terminals of the wind turbine generator (WTG) may become unacceptable low or high. Such unacceptable output voltages may be harmful for components of the wind turbine generator.
In case that the output voltage becomes too high or low the wind turbine generator may be disconnected from the grid connection to avoid damaging components of the wind turbine generator.
U.S. Pat. No. 8,710,689 discloses a wind energy installation including a rotor, a generator driven by the rotor, and a converter for generating electrical power which is output into a power supply system via a transformer. The installation also includes an open-loop control system having an open-loop converter control unit. The open-loop control system supplies an actuating signal for a reactive component to the converter. The installation further includes a voltage measurement device arranged on the transformer. The voltage signal of the voltage measurement device is applied to an input of a state-dependent setpoint value shifter, whose output signal is applied to a limitation module for the reactive component acting on the converter. With this configuration, the installation can be better protected and the transformer can be better utilized.